This invention relates to a curved bar apparatus for smoothing and guiding moving webs such as paper or textiles.
Moving webs such as paper or textiles are processed at relatively high speeds by passing them over and between rollers to and from various processing steps to which the web is subjected such as drying, printing, etc. During movement over the rollers, these webs have a tendency to form wrinkles or folds which are undesirable since non-uniform treatment of the wrinkled web surface will result. Presently, the most commonly employed means for smoothing the surface of a moving web is by passing the moving web over a bowed roller, the surface of which rotates about its central axis and wherein the bow is in a direction such that the central portion of the web is elevated above the ends of the web. This roller configuration applies a tensile force in the lateral direction of the web thereby stretching it and unfolding or collapsing any wrinkles therein. While this means is generally effective for its intended purpose, it has disadvantages primarily resulting from the high cost thereof. For example, the bowed rollers are constructed with a central bowed bar which is enclosed by a plurality of bearings around which bearings extends a rubber cylinder which also is bowed and which rotates in contact with the moving web. The bearings employed are expensive to produce and to maintain and therefore are undesirable. Furthermore, there is a friction force between the roller and web which results in undesirable wear of the roller surface.